A spindle motor in which a shaft and a sleeve are supported by a radial fluid bearing and a thrust bearing in a noncontact state via a bearing clearance and are relatively driven rotatively, a lubricant reservoir having one end communicating with the bearing clearance and another end communicating with the outside is provided on an outer peripheral side of the sleeve whose inner periphery opposes the shaft, and a lubricant supplying passage, which is a clearance of the lubricant reservoir on its side which communicates with the bearing clearance, is set to a size exhibiting capillarity. Bubbles in the lubricant inside the lubricant reservoir are discharged through the clearance communicating with the outside, and the bearing clearance is automatically lubricated stably through the lubricant supplying passage by means of capillarity.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A spindle motor with fluid hydrodynamic bearings, comprising: a shaft; a sleeve which is relatively rotatable with respect to said shaft via a bearing clearance between said shaft and said sleeve; and a lubricant reservoir formed as a gap between said sleeve and an opposite member of said sleeve, wherein said lubricant reservoir becomes more narrow toward said bearing clearance and said sleeve and said opposite member of said sleeve are not relatively rotatable with respect to each other, wherein a bearing lubricant of said lubricant reservoir is supplied to said bearing clearance by capillary action.
2. The spindle motor according to claim 1, wherein said lubricant reservoir has one end which communicates with said bearing clearance and another end which communicates with the outside atmosphere.
3. The spindle motor according to claim 1, wherein said lubricant reservoir is formed at an outer peripheral surface of said sleeve.
4. The spindle motor according to claim 1, wherein at least one of an outer peripheral surface of said sleeve and an inner peripheral surface of the opposite member is provided with a tapered surface.
5. The spindle motor according to claim 1, wherein at least one of an outer peripheral surface of said sleeve and an inner peripheral surface of said opposite member is provided with a tapered slit having a depth which is varied along an axial direction of said shaft.
6. The spindle motor according to claim 1, further comprising a thrust plate, wherein said lubricant reservoir communicates with an annular clearance between an outer peripheral surface of said thrust plate and an inner peripheral surface of said opposite member of said sleeve.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 23, 1999
August 7, 2001
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